Sticky Dots for Cancer Get Clinical Trial

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Getting cancer is bad enough. What usually kills people though is
when it spreads.

A new diagnostic technique approved for a human clinical trial
targets the root of the problem -- the cancer cells themselves --
with tiny tracers that atomically bond to rogue cells wherever
they appear in the body.

The study, which will take place at Memorial Sloan-Kettering
Cancer Center in New York, is intended to test if the sticky dots
work as well in humans as they did in mice and pigs.

"It's like flypaper," Louis Marzella, deputy director of medical
imaging products at the U.S. Food and Drug Adminstration, told
Discovery News. "It will stick to the item of interest.

For this clinical trial, scheduled to start in a few weeks,
doctors are recruiting five terminally ill melanoma patients who
will be injected with tiny silica spheres -- each less than 8
nanometers in diameter -- that enclose several molecules of dye.
A nanometer is about 40,000 times smaller than the width of an
average human hair.

The dots will be coated with polyethylene glycol, which the body
won't recognize as a foreign substance, labeled with radioactive
iodine to make them visible in follow-scans and sprinkled with
organic molecules that bind to tumor cells.

Dots that don't find cancer cells to latch on to are designed to
pass through the kidneys and out of the body in urine. Those that
find a target cell will fluoresce when exposed to near-infrared
light, revealing the location and spread of cancer.

"We want to find out what happens when particles are injected
into humans, are they as benign as they were when they were
injected into animals?" materials scientist and engineer Ulrich
Wiesner, with Cornell University, told Discovery News.

"We want to know a lot about the safety of these products," added
Marzella.

If successful, the nanoparticles will not only present doctors
with a powerful new imaging tool, they also could deliver
medications to kill cancer cells on contact, with far fewer side
effects than conventional treatments.

"That's the next level of complexity," Wiesner said. "It's
clearly something we want to do."

Eventually, cancer sticky dots, which can be illuminated by small
optical devices, could revolutionize cancer surgeries by
illuminating exactly where a doctor needs to cut.

"The only thing that currently guides surgeons is his or her
experience," Wiesner said. "We want to provide an engineering
parameter. This may really change things."